Paper making processes and system using enzyme and cationic coagulant combination

ABSTRACT

A method is described for making paper or paper board by applying a composition containing enzyme and cationic coagulant to papermaking pulp prior to paper forming to preferably improve drainage, retention, or both. Sheets of pulp from which paper or paperboard products are made with the method can exhibit excellent drainage, excellent retention of pulp fines, or both. The method also can be applied to other pulp treatments, such as waste water treatments. A system for making such treatments of paper furnish is also provided.

This application claims the benefit under 35 U.S.C. §119(e) of priorU.S. Provisional Patent Application No. 61/324,499, filed Apr. 15, 2010,which is incorporated in its entirety by reference herein.

BACKGROUND OF THE INVENTION

The present invention relates to paper making processes and system forthe processes. More particularly, the present invention relates to apaper making process and system using an enzyme and cationic coagulantcombination to improve cellulosic pulp drainage and/or retention.

Conventional paper making processes generally include the followingsteps: (1) forming an aqueous suspension of cellulosic fibers, commonlyknown as pulp; (2) adding various processing and paper enhancingmaterials, such as strengthening, retention, drainage aid and/or sizingmaterials, or other functional additives; (3) sheeting and drying thefibers to form a desired cellulosic web; and (4) post-treating the webto provide various desired characteristics to the resulting paper, suchas surface application of sizing materials, and the like. Some cellulaseenzymes can be used to treat cellulosic fiber and improve the drainageof the fiber suspension slurry. However, enzyme usage has required anadditional pretreatment process of heating the cellulosic pulp, such aspreheating the pulp to approximately 50° C. for about 30-120 minutesbefore enzyme addition. Additional energy consumption and equipmentinstallation is required for such preheating operations for enzymeusage. Further, enzymes can be costly, and enzyme application forpapermaking would result in significant increases in production cost.

The present investigators have seen a need for additives useful inpapermaking processing that can produce paper with improved cellulosicpulp drainage and retention in cost reduced manners.

SUMMARY OF THE INVENTION

A feature of the present invention is to provide a papermaking methodwith improved cellulosic pulp drainage and/or retention.

Another feature of the present invention is to provide a papermakingmethod using enzymes without requiring preheating treatments of the pulpto obtain improved cellulosic pulp drainage and retention.

An additional feature of the present invention is to provide apapermaking system operable for using enzymes without requiring pulppreheating equipment to obtain improved cellulosic pulp drainage and/orretention.

Additional features and advantages of the present invention will be setforth in part in the description which follows, and in part will beapparent from the description, or may be learned by practice of thepresent invention. The objectives and other advantages of the presentinvention will be realized and obtained by means of the elements andcombinations particularly pointed out in the written description andappended claims.

To achieve these and other advantages and in accordance with thepurposes of the present invention, as embodied and broadly describedherein, the present invention relates to a method of making paper orpaperboard. The method includes applying a composition containing atleast one enzyme and at least one cationic coagulant to a paper makingpulp to form a treated pulp. The enzyme and cationic coagulant can beapplied to a paper making pulp at the same time as a pre-mixture or asseparately added components. The enzyme and cationic coagulant, asanother option, can be added sequentially within a short enough periodof time to permit the components to interact in combination with thepulp. The treated pulp may also be further treated with at least oneflocculant. The resulting treated pulp is then formed into a sheet ofpulp, which can have improved drainage and/or retention propertiescompared to conventional treatments that do not use a composition havingthe enzyme and cationic coagulant combination.

The present invention also relates to a papermaking system for carryingout methods, such as above-described. The system can include a supply ofpapermaking pulp, a processing unit for forming the pulp into a paper orpaperboard having at least a screen for collecting pulp and a papersheet forming processing unit receiving pulp from the screen, a supplyof a composition containing at least an aqueous dispersion of at leastone enzyme and at least one cationic coagulant and a feeding device forfeeding the composition to the pulp for application thereto prior topaper forming, and a supply of at least one flocculant and a feedingdevice for feeding the flocculant to the treated pulp downstream ofwhere the enzyme and cationic coagulant composition is applied to thepulp, and a white water silo for white water recirculation.

Although illustrated for papermaking processing, the use of the enzymeand cationic coagulant combination also can relate to its applicationfor other cellulosic fiber contained material for enhanced dewatering invarious other industries, such as waste water treatments. The presentinvention can relate, for example, to a method of treating cellulosicpulp comprising applying a composition comprising enzyme and cationiccoagulant to a cellulosic pulp dispersed or otherwise contained in aliquid medium to form a treated pulp, and optionally dewatering thetreated pulp.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are only intended to provide a further explanation of the presentinvention, as claimed.

As used herein, “coagulant” refers to a material that can create largerparticles by neutralizing electrical charges surrounding small particlesin solution, e.g., neutralize repulsive electrical charges (e.g.,negative charges) surrounding particles, allowing them to “sticktogether” creating clumps or flocs.

“Flocculant” refers to a material that can facilitate the agglomerationor aggregation of the coagulated particles to form larger floccules.

“Enzyme” refers to a material comprising a protein or conjugated proteinfunctionable as a biochemical catalyst.

The accompanying drawings, which are incorporated in and constitute apart of this application, illustrate several aspects of the presentinvention and together with the description, serve to explain theprinciples of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart showing a paper making method according to thepresent invention.

FIG. 2 is a flow chart showing a paper making method according to thepresent invention.

FIG. 3 shows the effects of enzyme combined with cationic coagulant onOCC furnish drainage (g/50 sec) and turbidity (NTU) at an enzymeaddition level of 5% as related in Example 1.

FIG. 4 shows the effects of enzyme combined with cationic coagulant onOCC furnish drainage (g/30 sec) and turbidity (NTU) at an enzymeaddition level of 1% as related in Example 1.

FIG. 5 shows the effects of enzyme combined with cationic coagulant onOCC furnish drainage (g/30 sec) and turbidity (NTU) at an enzymeaddition level of 0.2% as related in Example 1.

FIG. 6 shows the effects of enzyme combined with cationic coagulant onNewsprint furnish drainage (g/30 sec) and turbidity (NTU) at 1% enzymeaddition level as related in Example 1.

FIG. 7 shows the effects of enzyme combined with cationic coagulant onOCC furnish drainage (g/30 sec) and turbidity (NTU) at the equal cost tothe regular coagulant without enzyme addition as related in Example 1.

FIG. 8 compares the furnish drainage (g/30 sec) of cationic coagulant inwhite water recirculation with an enzyme and cationic coagulantcombination and without the combination as related in Example 1.

FIG. 9 compares the furnish turbidity (NTU) of cationic coagulant inwhite water recirculation with an enzyme and cationic coagulantcombination and without enzyme combination as related in Example 1.

FIG. 10 compares the furnish drainage (g/30 sec) of cationic coagulantin white water recirculation with an enzyme and cationic coagulantcombination, cationic coagulant without enzyme combination, and enzymewithout cationic coagulant combination, as related in Example 2.

FIG. 11 compares the furnish turbidity (NTU) of cationic coagulant inwhite water recirculation with an enzyme and cationic coagulantcombination, cationic coagulant without enzyme combination, and enzymewithout cationic coagulant combination, as related in Example 2.

FIG. 12 shows the effects of enzyme combined with cationic coagulant onOCC furnish drainage (g/50 sec) at enzyme addition levels of 5%, 10%,and 15% as related in Example 3.

FIG. 13 shows the effects of enzyme combined with cationic coagulant onOCC furnish drainage (g/50 sec) at contact times of 0 minutes, 20minutes, and 40 minutes as related in Example 3.

FIG. 14 shows the effects of enzyme combined with cationic coagulant onOCC furnish drainage (g/50 sec) at temperatures of 20° C., 40° C., and60° C. as related in Example 3.

FIG. 15 shows the effects of enzyme combined with cationic coagulant onOCC furnish drainage (g/50 sec) for different coagulants of BUFLOC® 5031and BUFLOC® 597, and flocculant of BUFLOC® 5511 as related in Example 3.

FIG. 16 shows the effects of enzyme combined with cationic coagulant,coagulant alone, and flocculant alone, on OCC furnish drainage (g/50sec) as related in Example 3.

FIG. 17 shows the effects of enzyme combined with cationic coagulant onOCC furnish turbidity (NTU) at enzyme addition levels of 5%, 10%, and15% as related in Example 3.

FIG. 18 shows the effects of enzyme combined with cationic coagulant onOCC furnish turbidity (NTU) at contact times of 0 minutes, 20 minutes,and 40 minutes as related in Example 3.

FIG. 19 shows the effects of enzyme combined with cationic coagulant onOCC furnish turbidity (NTU) at temperatures of 20° C., 40° C., and 60°C. as related in Example 3.

FIG. 20 shows the effects of enzyme combined with cationic coagulant onOCC furnish turbidity (NTU) for different coagulants of BUFLOC® 5031 andBUFLOC® 597, and flocculant of BUFLOC® 5511 as related in Example 3.

FIG. 21 shows results of a simulation of white water recirculationshowing effects of enzyme on drainage (g) related to time (seconds) asrelated in Example 3.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The present invention provides methods of making paper or paperboard.The enzyme(s) and cationic coagulant(s) can be applied to a paper makingpulp at the same time or sequentially within a short enough period oftime to permit the components to interact in combination with the pulp.The enzyme(s) and cationic coagulant(s) can be pre-combined as apre-mixture, and then added together in a common composition to thepulp. In another option, the enzyme(s) and cationic coagulant(s) can beco-mixed in an addition pipeline or other feedline which feeds theresulting co-mixture to an introduction port(s), such as a port on apulp processing unit. In yet another option, the enzyme composition(s)and cationic coagulant(s) can be added separately and simultaneously tothe pulp from different introduction ports on the same processing unit.As another option, the enzyme composition and cationic coagulant can beintroduced sequentially, i.e., separately at separate times, from thesame or different introduction ports or locations on the papermakingsystem within a short period of time. In sequential addition, the enzymeand cationic coagulant components can be separately added in time withboth components brought into contact in the pulp within a short periodof time, for example, within about 5 minutes of each other, or withinabout 4 minutes of each other, or within about 2 minutes of each other,or within about 1 minute of each other, or within about 30 seconds ofeach other, or within shorter periods of time. After contacting the pulpwith the enzyme(s) and cationic coagulant(s), the resulting pulp can befurther processed and formed into a paper or paperboard. Sheets of pulpfrom which the paper or paperboard products are made can exhibitexcellent drainage and/or excellent retention of pulp fines, exceedingany expectations that may be drawn from the individual effects of theenzyme and cationic coagulant components. The improvements can besynergistic. Also, these improvements in drainage and retentionperformance can be obtained without the need to heat the pulp totemperatures of about 40° C. or greater prior to applying the enzyme tothe pulp. Flocculant(s) can be added to the pulp or pulp stream afteraddition of the enzyme and cationic polymer composition and before paperforming. For purposes of this patent application, the terms “pulp,”“stock,” and “paperstock” are used interchangeably. Also, when terms,such as enzyme or coagulant, are used in the singular, it is understoodthat more than one type can be used (e.g., one or more enzymes, one ormore coagulants, etc.).

The method of the present invention can be practiced on conventionalpaper making machines with modifications that can be easily made in viewof the present invention. The method of the present invention can bepracticed, for example, on a wet end assembly of a conventionalpapermaking machine with modifications that can be easily made in viewof the present invention. The method can employ many different types ofpaper making pulp or combinations thereof. Pulps treated on papermakingmachines with the enzyme and cationic coagulant composition exhibitimproved drainage performance, retention performance, or both. Forexample, the drainage (mass/time, e.g., g/30 sec) of pulp treated withthe enzyme and cationic coagulant can be, for example, at least about 5%greater, or at least about 10% greater, or at least about 25% greater,than treatment with only one of the enzyme or the cationic coagulant(i.e., without the enzyme or without the cationic coagulant). Forexample, a drainage of 100 g/30 sec obtained with treatment of a pulpfurnish with a composition containing either the cationic coagulant orthe enzyme, but not both, can be increased by treatment with acombination of the two components (e.g., as a pre-mixture), for example,to at least about 105 g/30 sec or greater, or to at least about 110 g/30sec or greater, or to at least about 125 g/30 sec or greater,respectively. The turbidity (NTU) of pulp, as a measure of both firstand colloidal retention, treated with the enzyme and cationic coagulantcan be, for example, at least about 5% less, or at least about 10% less,or at least about 25% less, than treatment with only one of the enzymeor the cationic coagulant (i.e., without the enzyme or without thecationic coagulant). In one option, the above-indicated percentagechanges in drainage, turbidity, or both, can be determined relative to avalue observed when only the cationic coagulant is used (i.e., withoutthe enzyme). In another option, the above-indicated percentage changescan be determined relative to a value observed when only the enzyme isused (i.e., without the cationic coagulant). It also has been found thatthe combined use of the enzyme with cationic coagulant allows for enzymeaccumulation in white water recirculation or other closure recirculationin papermaking methods for reducing overall enzyme additionrequirements, while remaining sufficient for performing desiredenzymatic reactions with the fiber in the papermaking method. Themethods of the present invention make it feasible to eliminatepretreatments of cellulosic pulp before enzyme application. No heattreatment processing and associated heating equipment for pulp isrequired before the enzyme application in the methods of the presentinvention for obtaining bulk low consistency pulp, which can translateinto significant energy and equipment savings. For example, the pulpdoes not need to be heated to a temperature of about 40° C. or greater,or about 45° C. or greater, or about 50° C. or greater, prior toapplying the enzyme and cationic coagulant composition to the pulp inorder for the enzyme to have the desired activity with respect to thefiber. Stated another way, the pulp can be maintained at a temperatureor allowed to be stored at a temperature below about 40° C., or belowabout 35° C., or below about 33° C. (e.g., 10° C. to 39° C.), at alltimes prior to applying the enzyme and cationic coagulant composition tothe pulp in the methods of the present invention, without impairing theability of the enzyme to have the desired activity with respect to thepulp fiber. Further, the enzyme combination with cationic coagulant canbe applied as a treatment for papermaking pulp at any convenientaddition point or points in the papermaking system prior to paperforming, without requiring other changes of an existing wet-end program.Also, through the enzyme and cationic coagulant combination, thecoagulant dosage can be significantly reduced while still acquiringsignificant improvements on pulp drainage and turbidity withoutincreasing chemical additives cost. In addition or as an alternative tothe above uses and benefits, the enzyme and cationic coagulantcomposition can be applied as a coagulant source for any program thatrequires coagulant in a papermaking process. In another option, theenzyme and cationic coagulant composition can be applied as an enzymesource for any program that requires an enzyme treatment process forvarious pulps.

The enzyme component of the enzyme used with a cationic coagulant totreat the pulp according to this invention can include, for example, anenzyme having cellulytic activity. For example, the enzyme can haveactivity that affects the hydrolysis of fiber. The enzyme can be, forexample, cellulase, hemicellulase, pectinase, β-glucanase, CMCase,amylase, glucosidase, galactosidase, lipase, protease, lacase, or anycombinations thereof. The cellulase enzyme can be, for example, acellulase, such as an endo-cellulase, exo-cellulase, cellobiase,oxidative cellulase, cellulose phosphorylases, or any combinationsthereof. Endo-cellulases that can be used, for example, areendoglucanase with binding domain (NOVOZYM® 476, Novozymes),endoglucanase enriched with high cellulase units (NOVOZYM® 51081,Novozymes), or combinations thereof, or other known or usefulendo-cellulases. A single type of enzyme or a combination of two or moredifferent types of enzymes can be used jointly with the cationiccoagulant.

Cellulases generally are enzymes that degrade cellulose, a linearglucose polymer occurring in the cell walls of plants. Hemicellulases(e.g., xylanase, arabinase mannose) generally are involved in thehydrolysis of hemicellulose, which, like cellulose, is a polysaccharidefound in plants. The pectinases generally are enzymes involved in thedegradation of pectin, a carbohydrate whose main component is a sugaracid. β-glucanases are enzymes involved in the hydrolysis of β-glucanswhich are also similar to cellulose in that they are linear polymers ofglucose. Liquid enzymatic compositions containing cellulases also areavailable under the names Celluclast® and Novozym® 188, which are bothsupplied by Novo Nordisk.

The following paragraphs provide examples of enzymes that can be usedalone or in combination in the present invention. PULPZYM® product,available from Novo Nordisk, and ECOPULP® product, from AlkoBiotechnology, are two examples of commercially available liquidenzymatic compositions containing xylanase-based bleaching enzymes.

As a class, hemicellulases can include hemicellulase mixture andgalactomannanase. Commercial liquid enzymatic compositions containinghemicellulases are available as PULPZYM® from Novo, ECOPULP® from AlkoBiotechnology and Novozym® 280 and Gamanase™, which are both products ofNovo Nordisk.

Pectinases consist of endopolygalacturonase, exopolygalacturonase,endopectate lyase (transeliminase), exopectate lyase (transeliminase),and endopectin lyase (transeliminase). Commercial liquid enzymaticcompositions containing pectinases are available under the namesPectinex™ Ultra SP and Pectinex™*, both supplied by Novo Nordisk.

β-glucanases are comprised of lichenase, laminarinase, and exoglucanase.Commercial liquid enzymatic compositions containing β-glucanases areavailable under the names Novozym® 234, Cereflo®, BAN, Finizym®, andCeremix®, all of which are supplied by Novo Nordisk.

Two additional classes of industrially and commercially useful enzymesare lipases and phospholipases. Lipases and phospholipases are esteraseenzymes.

Novo Nordisk markets two liquid enzyme preparations under the namesResinase™ A and Resinase™ A 2X.

Alkaline lipases can be used. Commercial liquid enzymatic compositionscontaining lipases are available under the names Lipolase 100, Greasex50L, Palatase™ A, Palatase™ M, and Nipozyme™, which are all supplied byNovo Nordisk.

With respect to the commercially useful phospholipases, pancreaticphospholipase A₂ can be used. Isomerases can be used.

Redox enzymes can be used. Redox enzymes can include peroxidase,superoxide dismutase, alcohol oxidase, polyphenol oxidase, xanthineoxidase, sulfhydryl oxidase, hydroxylases, cholesterol oxidase, laccase,alcohol dehydrogenase, or steroid dehydrogenases.

As indicated, in one option, the enzyme and cationic coagulantcomponents can be premixed into a common composition used to treat apulp. An enzyme preformulated in a liquid composition can be used as thesource of the enzyme combined with the cationic coagulant component. Acellulytic enzyme composition can contain, for example, from about 5% byweight to about 20% by weight enzyme. These enzyme compositions canfurther contain, for example, polyethylene glycol, hexylene glycol,polyvinylpyrrolidone, tetrahydrofuryl alcohol, glycerine, water, andother conventional enzyme composition additives, as for example,described in U.S. Pat. No. 5,356,800, which is incorporated herein inits entirety by reference.

Other suitable enzymes and enzyme-containing compositions include thosesuch as described in U.S. Pat. No. 5,356,800, U.S. Pat. No. 4,923,565,and International Patent Application Publication No. WO 99/43780, allincorporated herein in their entireties by reference. Other exemplarypaper making pulp-treating enzymes are BUZYME® 2523 and BUZYME® 2524,both available from Buckman Laboratories International, Inc., Memphis,Tenn.

The enzyme can be added to the pulp in an amount, for example, of fromabout 0.01% by weight to about 10% by weight enzyme based on the dryweight of the pulp, or from about 0.05% by weight to about 5% by weight,or from about 0.1 by weight to about 2.5% by weight, or from about 0.2by weight to about 1.5% by weight enzyme based on dry weight of thepulp, though other amounts can be used. These addition amounts of theenzyme relative to pulp can apply to use of pre-mixtures of the enzymeand cationic coagulant in a common composition, and also the otheraddition options indicated herein for introducing the enzyme andcationic coagulant separately to pulp (simultaneously or sequentially).Any amount, percentage, or proportion of enzyme described herein can beon an active enzyme basis. For example, an enzyme amount referred to as1% by weight enzyme can refer to 1% by weight active enzyme.

The cationic coagulant component can be or include a cationic organicpolymer coagulant, an inorganic cationic coagulant, or combinationsthereof. In addition to the synergistic affects with the enzyme, thecationic coagulant can reduce the negative surface charges present onparticles in the paperstock, particularly, the surface charges of thecellulosic fines and mineral fillers, and thereby can accomplish somedegree of agglomeration of such particles.

Cationic organic polymer coagulants can be, for example, cationicstarch(es), polyamine, polyamidoamine-glycol, polyvinylamine (PVAm),polyethylene imine, polydiallyldimethylammonium chloride (Poly-DADMAC),glyoxalated cationic polyacrylamide, copolymer of vinylamine andacrylamide, or any combinations thereof. The cationic coagulant can beor include polyacrylamide(s). The cationic coagulant can be considered,for purposes of the present invention, to be a coagulant and/or act as aflocculant. The cationic coagulant can be synthetic, natural, or acombination thereof.

The cationic organic polymer coagulant can be a water-soluble, lowmolecular weight, highly charged cationic polymer. The molecular weight(number average M_(w)) of the cationic organic polymer coagulant can be,for example, from about 1,000 to about 25,000,000, or from about 2,000to about 1,000,000, or from about 5,000 to about 750,000, or from about10,000 to 500,000, or from about 2,000,000 to 20,000,000, or from about5,000,000 to 15,000,000, or from about 10,000,000 to 20,000,000.Cationic polyvinylamines can include those described in U.S. Pat. No.4,421,602 and U.S. Patent Application Publication No. 2009/0314446 A1,both of which are incorporated herein in their entireties by reference.The cationic organic polymers can be or include, for example, thefollowing commercially available polymers: BUFLOC® 5031, a low molecularweight cationic polyamine having a 100% charge density and a molecularweight in the range of from about 100,000 to about 300,000; BUFLOC®5551, a cationic polyvinylamine having a 100% charge density and amolecular weight in the range of from about 2000 to about 4000; andBUFLOC® 597, a cationic modified polyethylene imine having a 100% chargedensity and a molecular weight in the range of from about 2,000,000 toabout 3,000,000, all available from Buckman Laboratories International,Inc. (Memphis Tenn.). For purposes herein, molecular weights aredetermined based on intrinsic viscosity as the analytic technique.

The amount of cationic organic polymer used as the cationic coagulantmay vary depending on the specific chemical used, and generally can beadded to the pulp in an amount, for example, of from about 0.5 poundcationic organic polymer per ton paperstock, based on dried solids ofthe pulp, or in an amount from about 0.5 pound to about 8 pounds per tonof paperstock, or from about 1 pound to about 6 pounds per ton ofpaperstock, or from about 1.5 pounds to about 4 pounds per ton ofpaperstock, or from about 2 pounds to about 3 pounds cationic organicpolymer per ton of paperstock, based on the dried solids of the pulp,though other amounts can be used. These addition amounts of the cationicorganic coagulant relative to pulp can apply to use of pre-mixtures ofthe enzyme and cationic organic coagulant in a common composition, andalso the other addition options indicated herein for introducing theenzyme and cationic coagulant separately to pulp.

Cationic coagulants can be or include inorganic cationic chemicals(e.g., aluminum sulfate (alum), aluminum chloride, ferric chloride,ferric sulfate), cationic inorganic polymers (e.g., polyaluminumchloride (PAC) polyaluminum sulfate (PAS), polyaluminum sulfate silicate(PASS)), water-dispersible cationic mineral particles (e.g., cationicalumina mineral particles, a cationic colloidal silica sol), aluminumchlorohydrate (ACH), or any combinations thereof.

PAC can be used in the form of a very low molecular weight cationiccharged dipolymer, such as those available from Buckman LaboratoriesInternational, Inc., as BUFLOC® 5041 or BUFLOC® 569. The cationicmicroparticle can be a cationic natural or synthetic hectorite,bentonite, zeolite, alumina sol, or any combinations thereof. Exemplarycationic mineral particles for use in the enzyme and coagulantcompositions of the present invention can include the fibrous cationiccolloidal alumina microparticles such as described in U.S. Pat. No.6,770,170 B2, the fibrous alumina products obtainable by the processesdescribed in U.S. Pat. No. 2,915,475 to Bugosh, and those described inWO 97/41063, all of which are incorporated herein in their entireties byreference.

The amount of inorganic cationic coagulant may vary depending on thespecific chemical or mineral used, and generally can be added to thepulp in an amount, for example, of at least about 0.1 pound per ton ofpaperstock, based on dry solids of the pulp, or from about 0.2 pound perton of paperstock to about 5.0 pounds per ton of paperstock, or fromabout 0.3 pound per ton of paperstock to about 4.0 pounds per ton ofpaperstock, or from about 0.5 pound to about 3.0 pounds per ton ofpaperstock, or from about 1.0 pound to about 2.0 pounds per ton ofpaperstock, based on dry solids of the pulp, though other amounts can beused. These addition amounts of the inorganic cationic coagulantrelative to pulp can apply to use of pre-mixtures of the inorganiccationic coagulant and an enzyme in a common composition, and also theother addition options indicated herein for introducing the enzyme andcationic coagulant separately to pulp.

As several illustrations, the cationic coagulant used in combinationwith the enzyme can include at least one or any combination of: 1) asingle type of cationic organic polymer (e.g., polyamine); 2) blends ormixtures of different cationic organic polymers in combination (e.g., apolyamine and poly-DADMAC combination; 3) a cationic organic polymer andcationic inorganic chemical coagulant blend (e.g., a polyamine and PACcombination); 4) a cationic inorganic polymer or cationic inorganicchemical or cationic mineral particles, or any combination thereof. Asan option, the coagulant(s) used in the coagulant and enzyme compositionis an organic polymer which has cationic charge functionalitiesrepresenting, for example, at least 1%, at least 10%, at least 25%, atleast 50%, at least 75%, at least 90%, or at least 95%, or at least 99%,or up to 100%, of the total ionic charge bearing functionalities of thepolymer. In another option, the coagulant can be a multifunctionalorganic polymer having both cationic and anionic chargedfunctionalities. In an option, the coagulant can be an organic polymerwhich has a net cationic charge if multifunctional. In another option,the enzyme and cationic coagulant composition can further include atleast one anionic coagulant compound (such as an anionic organicpolymer, an inorganic anionic compound, or both) as a separatelyintroduced component from the cationic coagulant compound or compoundsin the composition. Anionic components may cause deposits (e.g., gels)in the pulp or white water. Any amounts of anionic components, anionicfunctionalities on components, or both, present in the coagulant andenzyme composition can be controlled, for example, to reduce or avoidformation of such deposits and to amounts that do not impair the pulpdrainage and retention performance of cationic coagulant and enzymecomposition. As an option, a pre-mixture or co-mixture of the coagulantand enzyme composition can be used free or substantially free of anyanionic components that cause gel deposits, impair the pulpdrainage/retention performance of the composition, or both.

As indicated, in an option, the enzyme and cationic coagulantcomposition and components thereof can be introduced into thepapermaking process at the same time to form a pre-treated pulp. As alsoindicated, the enzyme and cationic coagulant can be introduced to a pulpor pulp stream in the papermaking system at the same time as a pre-mixedcomposition. As options, the enzyme and cationic coagulant can beintroduced as separate additions that blend together during or afteraddition into the pulp. As an indicated option, for example, the enzymeand cationic coagulant can be added separately and simultaneously to thepulp from different introduction ports on the same processing unitwithin the papermaking system. As another indicated option, the enzymecomposition and cationic coagulant can be introduced sequentially (e.g.,at separate, nonoverlapping addition times) from the same or differentintroduction ports or locations on the papermaking system or processingunit(s) thereof, wherein the enzyme and cationic coagulant can contactthe pulp fiber to be treated within a short period of time, for example,within about 5 minutes of each other, or within about 4 minutes of eachother, or within about 2 minutes of each other, or within about 1 minuteof each other, or within about 30 seconds of each other, or within 10seconds of each other, or within 5 seconds of each other, or within 3seconds of each other, or within 2 seconds of each other, or within 1second of each other, or within 0.5 seconds of each other, or within0.25 seconds of each other, or within about 0.25 seconds to about 5minutes of each other, or within about 1 minute to about 5 minutes ofeach other, or within about 2 to about 5 minutes of each other, orwithin about 2 minutes to about 4 minutes of each other.

The enzyme and cationic coagulant compositions based on pre-mixtures ofthese components can have, for example, from about 1% by weight to about99% by weight enzyme and from about 99% by weight to about 1% by weightcationic coagulant, or from about 1% by weight to about 25% by weightenzyme and from about 99% by weight to about 75% by weight cationiccoagulant, or from about 2.5% to about 20% by weight enzyme and fromabout 97.5% to about 80% by weight cationic coagulant, or from about 5%to about 15% by weight enzyme and from about 95% to about 85% by weightcationic coagulant, on a dry solids weight basis. When prepared as apre-mixture, the composition based on the enzyme and cationic coagulantcomponents can be formulated by sequentially or simultaneously combiningthe components in a fluid medium, such as water. The order of additionof the components is not limited. The various ingredients that form theenzyme and coagulant compositions of the present invention can be mixedtogether using conventional mixing techniques, such as a mixer, blender,stirrer, and/or an open vessel. Before and/or following aqueousdispersion of the enzyme and cationic coagulant, the pH of the resultingcombination generally can be controlled, for example, to a defined levelof a pH of from about 3 to about 10, or a pH of from about 4 to about10, or a pH of from about 7.0 to about 10.0, and more suitably fromabout 8.0 to about 9.0. These pH ranges can apply to the compositionand/or to the composition in an aqueous solution. Adjustment of pH ofthe composition can be accomplished, for example, through the additionof either sodium hydroxide or ammonium hydroxide (aqueous ammonia). Theenzyme and cationic coagulant composition may include one or moreadditives, such as dyes, pigments, defoamers, biocides, pH adjustingagents, and/or cationic starch, and/or other conventional paper makingor processing additives. The optional additives, if used, should notimpair the unique combined effects of the enzyme and cationic coagulant,such as with respect to drainage and/or retention enhancements. Asindicated, anionic components, for example, may cause deposits (gels) inthe pulp or white water. The enzyme and cationic coagulant compositioncan contain, for example, less than about 3% by weight, or less than 2%by weight, or less than 1% by weight, or less than 0.5% by weight, ofanionic components that cause deposits or gels. The enzyme and cationiccoagulant composition, as a pre-mixture, can be prepared as a physicallystable aqueous dispersion, which can be more stable, for example, atfrom about 10% by weight to about 60% by weight total solids, or fromabout 25% to about 50% by weight total solids, or from about 35% byweight total solids. At about 45% by weight total solids, the viscositycan tend to stay in a pourable range. Higher solids levels may tend togradually thicken during any storage before use.

The enzyme and cationic coagulant compositions, when prepared aspre-mixtures of these components, can be prepared as masterbatches fordilution at a later time or the desirable concentration can be made atthe same time that the composition is prepared. The enzyme and cationiccoagulant composition can be prepared on-site or off-site or parts orcomponents of the composition can be prepared or pre-mixed off-site oron-site prior to the ultimate formation of the composition. Thecompositions comprising the pre-mixtures of enzyme and cationiccoagulant can be formed immediately prior to their introduction into thepapermaking process or sheet making process, or the compositions can beprepared beforehand, such as before use, minutes before use, hoursbefore use, or days or weeks or months before use, and preferably withinabout 2-3 weeks of usage. For instance, when the compositions areintroduced as a pre-mixture of enzyme and cationic coagulant, thepre-mixture can be made about 1 to about 100 seconds before theirintroduction into the papermaking process, or from about 1 hour to about5 hours, or from about 1 hour to about 10 hours, or about 1 hour toabout 24 hours before use, or from about 1 day to about 7 days, or about1 day to about 30 days, or about 1 day to about 60 days, or about 1 dayto about 180 days, before use.

As indicated, the pulp or stock can be treated with the compositionincluding both the enzyme and cationic coagulant as a pre-mixture at anylocation in the papermaking system before formation of the paperweb onthe wire, e.g., an addition point prior to the headbox in the system.The separate additions of these components to the pulp according toother indicated options also can be done at any of these locations inthe papermaking system.

The enzyme and cationic coagulant composition comprising a pre-mixtureof these components can be added to paperstock, for example, in anamount of at least about 0.5 pound per ton of paperstock, based on driedsolids of the pulp, or at least about 1 pound per ton of paperstock, orfrom about 0.5 to about 10 pounds per ton of paperstock, or from about0.75 to about 7.5 pounds per ton of paperstock, or from about 1 to about5 pounds per ton of paperstock, or from about 1.25 to about 4 pounds perton of paperstock, or from about 1.5 to about 3 pounds per ton ofpaperstock, or from about 0.5 to about 1.5 pounds per ton of paperstock,based on dried solids of the pulp in the paperstock, though otheramounts can be used. Where separate additions of the enzyme and cationiccoagulant to the pulp are used according to other indicated optionsherein, the combined amounts of these components relative to the pulpalso can be within one or more of these above-indicated ranges.

A flocculant can be added before or after addition of the enzyme andcationic coagulants to the paperstock, and typically is added afteraddition. The flocculant can be added, for example, after addition ofthe composition and/or various shear steps of any refining processapplied to the treated pulp. The flocculant can be, for example, acationic, anionic, nonionic, zwitterionic, or amphoteric polymerflocculant which can further increase retention and/or drainage in apapermaking furnish to the performance enhancements provided by theenzyme and cationic coagulant composition.

Suitable flocculants generally can have molecular weights (average MW),for example, in excess of about 1,000,000, or in excess of about5,000,000, or in excess of about 20,000,000, or in excess of about1,000,000 up to about 25,000,000. One polymeric flocculent can beprepared by vinyl addition polymerization of one or more cationic,anionic, or nonionic monomers; by copolymerization of one or morecationic monomers with one or more nonionic monomers; bycopolymerization of one or more anionic monomers with one or morenonionic monomers; by copolymerization of one or more cationic monomerswith one or more anionic monomers and optionally one or more nonionicmonomers to produce an amphoteric polymer; or by polymerization of oneor more zwitterionic monomers and optionally one or more nonionicmonomers to form a zwitterionic polymer. One or more zwitterionicmonomers and optionally one or more nonionic monomers may also becopolymerized with one or more anionic or cationic monomers to impartcationic or anionic charge to the zwitterionic polymer.

The flocculant can be used in solid form, as an aqueous solution, as awater-in-oil emulsion, or as dispersion in water. Representativecationic polymers include, for example, copolymers and terpolymers of(meth)acrylamide with dimethylaminoethyl methacrylate (DMAEM);dimethylaminoethyl acrylate (DMAEA); diethylaminoethyl acrylate (DEAEA);diethylaminoethyl methacrylate (DEAEM); or their quaternary ammoniumforms made with dimethyl sulfate, methyl chloride, or benzyl chloride.The flocculant can include, for example, dimethylaminoethylacrylatemethyl chloride quaternary salt-acrylamide copolymers and sodiumacrylate-acrylamide copolymers and hydrolyzed polyacrylamide polymers.The flocculant can be a polyacrylamide(s).

The flocculant can be added, for example, in an amount of at least about0.001 pound flocculant per ton of paperstock, based on dried solids ofthe pulp, or from about 0.01 to about 10 pounds per ton of paperstock,or from about 0.1 to about 6 pounds per ton of paperstock, or from about0.5 to about 4 pounds flocculant per ton of paperstock, or from about 1to about 3 pounds flocculant per ton of paperstock, based on the driedsolids of the pulp in the paper furnish, though other amounts can beused.

The enzyme and cationic coagulant, as part of a single pre-mixedcomposition or as separate components, can be added to many differenttypes of papermaking pulp, stock, or combinations of pulps or stocks.For example, the pulp may comprise virgin pulp and/or recycled pulp,such as virgin sulfite pulp, broke pulp, kraft pulp, soda pulp,thermomechanical pulp (TMP), alkaline peroxide mechanical pulp (APMP),chemithermomechanical pulp (CTMP), chemimechanical pulp (CMP),groundwood pulp (GP), mixtures of such pulps, and the like. The kraftpulp can be, for example, a hardwood kraft pulp, a softwood kraft pulp,or combinations thereof. The recycled pulp can be or include wastepaper, OCC, and other used paper products and materials. For example,there are a variety of mechanical pulping methods to which thisinvention can be applied. For example, thermomechanical pulp (TMP) usesa combination of heated wood chips and mechanical processes. StoneGroundwood (SGW) grinds or macerates the wood chips.Chemithermomechanical pulp (CTMP) uses a variety of chemicals, heat, andgrinding techniques to produce pulp. Different types of pulp requiredifferent types of paper although many papers can use a combination or“blend” of several different types of pulp and recycled/recovered paper.The papermaking pulp or stock can contain cellulose fibers in an aqueousmedium at a concentration, for example, of at least about 50% by weightof the total dried solids content in the pulp or stock, though otherconcentrations may be used. These pulp formulations can be referred toas fiber furnishes.

The pulps or stocks of the present invention may be treated with one ormore optional additives within the papermaking system. These optionaladditives may include, e.g., polymers such as cationic, anionic and/ornon-ionic polymers, clays, other fillers, dyes, pigments, defoamers, pHadjusting agents such as alum, sodium aluminate, and/or inorganic acids,such as sulfuric acid, microbiocides, supplemental water retention aidssuch as cationic colloidal alumina microparticles, supplementalcoagulants, supplemental flocculants, leveling agents, lubricants,defoamers, wetting agents, optical brighteners, pigment-dispersingagents, cross-linkers, viscosity modifiers or thickeners, or anycombinations thereof, and/or other conventional and non-conventionalpapermaking or processing additives. For example, the pH of the(treated) pulp generally, but not exclusively, can be controlled to adefined level of from about 4.0 to about 8.5, and more suitably fromabout 4.5 to about 8.0.

The pulps or stocks of the present invention may additionally be treatedwith one or more other components, including polymers such as anionicand non-ionic polymers, clays, other fillers, dyes, pigments, defoamers,pH adjusting agents such as alum, microbiocides, microparticles (e.g.,ACH), and other conventional papermaking or processing additives. Theseadditives can be added before, during, or after introduction of theenzyme and cationic coagulant composition.

The methods of the present invention can be practiced on any pulprelated applications, including, for example, where pulps are treatedand dewatered. The methods can be practiced, for example, onconventional paper making machines (such as a Fourdrinier type papermachine), for example, on wet end assemblies of paper making machines,with modifications that can be made in view of the present invention. Aflow chart of a paper making system for carrying out one of the methodsof the present invention is set forth in FIG. 1. FIG. 2 further showsoptional addition points for flocculant. It is to be understood that thesystem shown is exemplary of the present invention and is in no wayintended to restrict the scope of the invention.

In the system of FIG. 1, an enzyme and cationic coagulant composition ata desired concentration is combined with a flowing stream of papermakingpulp to form a treated pulp at one or more of the addition point Options1-6 shown in FIG. 1. To simplify this illustration (and the illustrationof FIG. 2), an enzyme and cationic coagulant composition is shown addedto the system as a pre-mixture of the enzyme and cationic coagulant.These and/or other addition points for the enzyme and cationic coagulantcomposition may be used as long as the composition is introduced beforepaper forming at the head box. The system can include a metering devicefor providing a suitable amount of the enzyme and cationic coagulantcomposition to the flow of pulp. Other metering or dosing devices alsocan be provided for the other additives and ingredients that may be usedduring the method.

A flocculant can be added before or after introduction of the enzyme andcoagulant composition, such as in one or more of additive introductionOptions 2A-6A shown in FIG. 2, and before the head box. For example,when the enzyme and cationic coagulant composition is added at Option 1,the flocculant could be added at any of the addition points shown asOptions 2A-6A in FIG. 2. When the enzyme and cationic coagulantcomposition is added at Option 2, the flocculant could be added at anyof Options 3A-6A, and so forth. The supply of enzyme and cationiccoagulant composition can be, for example, a holding tank having anoutlet in communication with an inlet of a tank or line in the system.The supply of flocculant can be, for example, a holding tank having anoutlet in communication with a tank or line in the system. Otheroptional additives may be added at other points along the flow of pulpor treated pulp through the system shown in FIG. 1, such as at one ormore of addition location Options 1-6. Conventional valving and pumpsused in connection with introducing the compositions and additives canbe used.

In FIG. 1, the supply of pulp shown represents a flow of pulp, as forexample, supplied from a pulp holding tank or silo. The supply of pulpshown in FIG. 1 can be a conduit, holding tank, or mixing tank, or othercontainer, passageway, or mixing zone for the flow of pulp. The pulp ispassed from the pulp tank through a refiner and then through a blendchest where necessary compositions and/or optional additives of theprocess may be combined with the pulp. The refiner has an inlet incommunication with an outlet of the treated pulp tank, and an outlet incommunication with an inlet of the blend chest. According to theembodiment of FIG. 1, the pulp in the blend chest is passed from anoutlet of the blend chest through a communication to an inlet of amachine chest where optional additives also may be combined with thetreated pulp. The blend chest and machine chest can be of anyconventional type known to those skilled in the art. The machine chestensures a level head, that is, a constant pressure on the treated pulpor stock throughout the downstream portion of the system, particularlyat the head box. From the machine chest, the pulp is passed to a whitewater silo and then to a fan pump, and then the pulp is passed through ascreen. The screen can be sized, for example, so as to allow watercontaining undesirable or unusable components of the white water (e.g.,fines, ash) to pass through the screen while retaining usable fibers onthe screen that can be incorporated into the fibrous material suppliedto the headbox. The screened pulp passes to a head box where a wetpapersheet is formed on a wire and drained. The wire section can includeequipment, for example, which is conventionally used and can be easilyadapted for use in methods of the present invention. Pulp collected as awet web on the forming wire can be further processed, for example, suchas one or more of further drained, pressed, dried, calendered, or otherprocessing such as typically used in a papermaking machine, before itmay be conveyed to a winder, and it can be further conveyed to eitherpaper sheeting or can be conveyed to coating and conversion stations(not shown). In the system of FIG. 1, drained pulp resulting frompapermaking in the headbox is recirculated to the white water silo. Thepulps or stocks also may be treated with one or more other optionaladditives introduced at addition points 1-6 or other locations withinthe system.

As shown in FIG. 1, for pulp treatment, the enzyme and cationiccoagulant composition can be added prior to the head box after thescreen, or added prior to the screen, or added prior to the fan pump, oradded prior to the whitewater silo, or added prior to the machine chest,or added prior to the blend chest, or added prior to the first refinerin a paper making process, or any combinations of these additionlocations. It can be useful to add the enzyme and cationic coagulant, atleast in part, far enough upstream of the head box to allow the enzymeand cationic coagulant components sufficient time and opportunity tointeract with the pulp without requiring any preheating of the pulp(e.g., heated temperatures of about 40° C. or greater) before treatmentwith the composition. Process temperatures in the papermaking system arenot limited, and can be, for example, from about 15° C. to about 70° C.,or from about 30° C. to about 60° C., or from about 15° C. to about 35°C., or from about 20° C. to about 34° C., or from about 25° C. to 33°C., or about 32° C., though other temperatures can be used. As anoption, the pulp temperatures of the treated pulp during at leastsubstantially (e.g., at least about 90% up to 100%) the entire time ofcontact of the enzyme and cationic coagulant composition with the pulpin the papermaking system can be maintained at from about 30° C. toabout 60° C. and the time of contact can be from about 1 minute to about150 minutes or other times. Other treatment temperatures and times withrespect to the pulp treated with the enzyme and cationic coagulantcomposition can be, for example, from about 30° C. to about 50° C. andthe time of contact can be from about 2 minutes to about 100 minutes, orfrom about 32° C. to about 40° C. and the time of contact can be fromabout 5 minutes to about 60 minutes, or other temperature and timecombinations.

A pulp or stock treated with the composition including both the enzymeand cationic coagulant can exhibit good dewatering during formation ofthe paperweb on the wire. The pulp or stock also can exhibit a desirablehigh retention of fiber fines and fillers in the paperweb products. Theaddition of flocculant, or microparticles, or both, to the treated pulpcan impart further improvements and enhancements, for example, such aswith respect to dewatering and retention performance. Althoughillustrated for papermaking processing, the use of the enzyme andcationic coagulant combination also can relate to its application forother cellulosic fiber contained material for enhanced dewatering inwaste water treatments and other industries.

The present invention includes the followingaspects/embodiments/features in any order and/or in any combination:

1. The present invention relates to a method of making paper orpaperboard comprising:

-   -   a) applying a composition comprising enzyme and cationic        coagulant to a paper making pulp to form a treated pulp; and    -   b) forming the treated pulp into paper or paperboard.

2. The method of any preceding or following embodiment/feature/aspect,wherein the pulp is kept at a temperature or temperatures below about40° C. prior to applying the composition to the pulp.

3. The method of any preceding or following embodiment/feature/aspect,wherein the composition comprises from about 1% by weight to about 99%weight enzyme and from about 99% by weight to about 1% by weightcationic coagulant, on a dry solids weight basis.

4. The method of any preceding or following embodiment/feature/aspect,wherein the enzyme is a cellulytic enzyme.

5. The method of any preceding or following embodiment/feature/aspect,wherein the enzyme is cellulase, hemicellulase, pectinase, β-glucanases,CMCase, amylase, glucosidase, galactosidase, lipase, protease, lacase,or any combinations thereof.

6. The method of any preceding or following embodiment/feature/aspect,wherein the enzyme is endoglucanase.

7. The method of any preceding or following embodiment/feature/aspect,wherein the cationic coagulant is a cationic organic polymer coagulant.

8. The method of any preceding or following embodiment/feature/aspect,wherein the cationic coagulant is a polyamine, polyacrylamide,polyamidoamine-glycol, polyvinylamine, polyethylene imine,polydiallyldimethylammonium chloride, glyoxalated cationicpolyacrylamide, cationic starch, or any combinations thereof.

9. The method of any preceding or following embodiment/feature/aspect,wherein the cationic coagulant is a polyamine, polyamidoamine-glycol,polyvinylamine, polyethylene imine, or any combinations thereof.

10. The method of any preceding or following embodiment/feature/aspect,wherein the cationic coagulant is an inorganic cationic coagulant.

11. The method of any preceding or following embodiment/feature/aspect,wherein the cationic coagulant is polyaluminum chloride, aluminumsulfate, water-dispersible alumina mineral particles, aluminum sulfate,aluminum chloride, ferric chloride, ferric sulfate, polyaluminumsulfate, polyaluminum sulfate silicate, cationic alumina mineralparticles, a cationic colloidal silica sol, aluminum chlorohydrate, orany combinations thereof.

12. The method of any preceding or following embodiment/feature/aspect,wherein the composition is added to the pulp in an amount of at leastabout 0.5 pound per ton based on the dried solids weight of the pulp.

13. The method of any preceding or following embodiment/feature/aspect,further comprising applying a flocculant to the pulp after applying thecomposition to the pulp and prior to paper forming.

14. The method of any preceding or following embodiment/feature/aspect,wherein pulp temperatures of the treated pulp during at leastsubstantially an entire time of contact of the composition with the pulpis maintained at from about 30° C. to about 60° C. and the time ofcontact is from about 1 minute to about 150 minutes.

15. The method of any preceding or following embodiment/feature/aspect,wherein the flocculant is added to the pulp in an amount of at leastabout 0.01 pound per ton based on the dried solids weights of the pulp.

16. The method of any preceding or following embodiment/feature/aspect,wherein the drainage (g/50 sec) is at least about 5% greater thantreatment of the pulp without the enzyme.

17. The method of any preceding or following embodiment/feature/aspect,wherein the turbidity (NTU) is at least about 5% less than treatment ofthe pulp without the enzyme.

18. A papermaking system comprising a supply of papermaking pulp, aprocessing unit for forming the pulp into a paper or paperboardcomprising a screen for collecting pulp and a paper sheet formingprocessing unit receiving pulp from the screen, a supply of acomposition comprising an aqueous dispersion of enzyme and cationiccoagulant and a composition feeding device for feeding the compositionto the pulp for application thereto prior to paper forming, and a supplyof flocculant and a flocculant feeding device for feeding the flocculantto the treated pulp downstream from where the enzyme and cationiccoagulant composition is applied to the pulp, and a white water silo forwhite water recirculation.

19. The system of any preceding or following embodiment/feature/aspect,wherein said processing unit for forming the pulp comprises a blendchest in communication with said supply of pulp, a fan pump incommunication with the blend chest, the screen in communication withsaid fan pump, and a head box as the paper forming processing unit incommunication with said screen.

20. The system of any preceding or following embodiment/feature/aspect,wherein said white water silo has a first inlet in communication withsaid machine chest, a second inlet in communication with said head box,and an outlet in communication with said fan pump.

The present invention can include any combination of these variousfeatures or embodiments above and/or below as set forth in sentencesand/or paragraphs. Any combination of disclosed features herein isconsidered part of the present invention and no limitation is intendedwith respect to combinable features.

The present invention will be further clarified by the followingexamples, which are intended to be purely exemplary of the presentinvention, in which parts and percentages are proportions by weightunless otherwise specified.

EXAMPLES Example 1

The drainage and retention properties of compositions exemplifying thepresent invention were examined.

Experimental

The following materials and protocols were used for the experiments.

Pulp Furnish:

Refined OCC pulps and white water were obtained from linerboardmanufacturers, such as Sonoco, Richmond, Va. and International Paper,Valliant Okla., as CSF 220, CSF 410, and as CSF 330. Newsprint furnishand white water were obtained from a Newsprint paper manufacturer, suchas Catalyst, Snowflake, Ariz., as CSF 50.

Chemicals and Dosages:

Cationic coagulant used for the experiments was a low molecular weightcationic polyamine (BUFLOC® 5031, Buckman Laboratories International,Inc.), and a typical dosage was 1.5 lb/ton (dry solids basis) for OCCfurnish and 4.0 lb/ton (dry solids basis) for Newsprint. The flocculantwas a polyacrylamide (BUFLOC® 5511, Buckman Laboratories International,Inc.), and was used at a typical dosage of 0.2 lb/ton (dry solids basis)for the tests. The selected enzyme was NOVOZYM® 51081 from Novozymes.Enzyme was premixed with cationic coagulant before applying it to pulpat designed addition levels. Different dosages or other additivesincluded in experiments are indicated where applicable.

Testing Procedure:

A MüTek™ RDF tester was applied for all drainage tests to measuredrainage and turbidity. The testing furnish consistency was 1.0%. Thechemical addition program was to add cationic coagulant first and followwith flocculant. To simulate white water circulation, the filtrate wascollected after testing and reused for next testing sample. The sampletemperature for all testing was controlled at 32° C.

Results

Tables 1-3 shows results for the effects of enzyme combined withcationic coagulant on OCC furnish drainage and turbidity at differentenzyme addition levels, 5%, 1% and 0.2% by weight, respectively. Forthese experiments, OCC furnish (CSF 220) was treated with the enzyme(NOVOZYM® 51081), 1.5 lb/ton coagulant (BUFLOC® 5031), and 0.2 lb/ton(dry solids basis) flocculant (BUFLOC® 5511) other than the 0.2% enzymerun, and also 1.0 lb/ton (dry solids basis) microparticle (BUFLOC® 5461)(anionic colloidal silica) was included. The results are graphicallyshown in FIGS. 3-5, respectively.

TABLE 1 White water Recirculations Drainage Turbidity No. g/50 sec NTU1st 317 386 2nd 437 297 3rd 465 243 4th 498 206 5th 488 203 6th 517 1907th 559 186

TABLE 2 White water Recirculations Drainage Turbidity No. g/50 sec NTU1st 329 376 2nd 449 336 3rd 485 300 4th 496 252 5th 518 227 6th 534 2127th 541 198

TABLE 3 White water Recirculations Drainage Turbidity No. g/50 sec NTU1st 348 539 2nd 457 353 3rd 501 326 4th 501 322 5th 502 299 6th 526 2817th 515 281 8th 521 240

Table 4 shows the results for the effects of enzyme combined withcationic coagulant on Newsprint furnish drainage and turbidity at 1% byweight enzyme addition level. For this experiment, Newsprint (CSF 50)was treated with 1% by weight enzyme (NOVOZYM® 51081), 4.0 lb/ton (drysolids basis) coagulant (BUFLOC® 5031), and 0.2 lb/ton (dry solidsbasis) flocculant (BUFLOC® 5511). The results are graphically shown inFIG. 6.

TABLE 4 White water Recirculations Drainage Turbidity No. g/30 sec NTU 1st 128 543  2nd 147 439  3rd 151 436  4th 158 397  5th 155  6th 159396  7th 163 380  8th 167 368  9th 173 353 10th 195 319 11th 195 31612th 190 324

Table 5 shows results for the effects of enzyme combined with cationiccoagulant on OCC furnish drainage and turbidity at 1% by weight enzymeaddition level at the equal cost to the regular coagulant without enzymeaddition. For this experiment, OCC furnish (CSF 410) was treated with 1%by weight enzyme (NOVOZYM® 51081), 2.0 lb/ton (dry solids basis)coagulant (BUFLOC® 5031), and 0.2 lb/ton (dry solids basis) flocculant(BUFLOC® 5511). The results are graphically shown in FIG. 7.

TABLE 5 White water Recirculations Drainage Turbidity No. g/30 sec NTU1st 328 336 2nd 350 260 3rd 396 238 4th 418 196 5th 438 192 6th 418 1907th 412 175

Table 6 shows the results for the effects of enzyme combined withcationic coagulant, and cationic coagulant without enzyme, on OCCfurnish drainage and turbidity in white water recirculation. For thisexperiment, OCC furnish (CSF 410) was treated with 1% by weight enzyme(NOVOZYM® 51081) or no enzyme, 1.5 lb/ton (dry solids basis) coagulant(BUFLOC® 5031), and 0.2 lb/ton (dry solids basis) flocculant (BUFLOC®5511). The results are graphically shown in FIGS. 8 and 9.

TABLE 6 Drainage Turbidity White water g/30 sec NTU RecirculationsEnzyme No Enzyme No No. combined enzyme combined enzyme 1st 425 412 176182 2nd 459 452 155 158 3rd 485 467 123 137 4th 524 469 113 126 5th 523474 109 123 6th 528 480 105 120 7th 536 481 104 121

Example 2

The drainage and retention properties of additional compositionsexemplifying the present invention were examined.

Experimental

The following materials and protocols were used for the experiments.

Pulp Furnish:

Refined OCC pulp was obtained from a linerboard manufacturer, such asSonoco, Richmond, Va., as CSF 220.

Chemicals and Dosages:

Cationic coagulant used for the experiments was BUFLOC® 5031 (BuckmanLaboratories International, Inc.), and the dosage was 1.5 lb/ton (drysolids basis) for OCC furnish. The flocculant was BUFLOC® 5511 (BuckmanLaboratories International, Inc.), and was used at a dosage of 0.2lb/ton (dry solids basis) for the tests. The selected enzyme wasNOVOZYM® 51081 from Novozymes at a dosage of about 1 wt %. Enzyme waspremixed with cationic coagulant before applying it to pulp at designedaddition levels.

Testing Procedure:

The testing procedure used was similar to that used in Example 1.

Results

Table 7 shows results for the effects of enzyme combined with cationiccoagulant, and cationic coagulant without enzyme combination, and enzymewithout cationic coagulant combination, on OCC furnish drainage andturbidity. The results are graphically shown in FIGS. 10 and 11,respectively. The results show that drainage was greater and turbiditywas lower for OCC furnish treated with enzyme combined with cationiccoagulant at all circulation times as compared to furnish treated withcationic coagulant without enzyme combination and furnish treated withenzyme without cationic coagulant combination.

TABLE 7 Drainage (g/30s) Turbidity (NTU) Cationic Cat. Coagulant EnzymeCationic Coagulant Enzyme Cationic Circulations only onlyCoagulant/Enzyme only only Coagulant/Enzyme 1 379 363 415 203 241 188 2399 360 469 188 237 129 3 446 367 473 152 233 118 4 453 370 475 149 231116 5 457 370 477 144 226 114 6 448 374 481 143 223 112 7 451 376 479134 222 111 8 446 381 484 134 220 105

Example 3

The drainage and retention properties of additional compositionsexemplifying the present invention were examined.

Experimental

The following materials and protocols were used for the experiments.

Pulp Furnish:

Refined OCC pulp was obtained from a linerboard manufacturer, such asSonoco, Richmond, Va., as CSF 220.

Chemicals and Dosages:

Cationic coagulants used for the experiments were low molecular cationicpolyamine (BUFLOC® 5031, Buckman Laboratories International, Inc.),polyamidoamine-glycol (BUFLOC® 597, Buckman Laboratories International),and low molecular weight cationic polyamine (BUFLOC® 5551, BuckmanLaboratories International, Inc.). The coagulant dosage was 1.5 lb/ton(dry solids basis). The flocculant was a polyacrylamide (BUFLOC® 5511,Buckman Laboratories International, Inc.), and was used at dosage of 0.2lb/ton (dry solids basis) for all tests. The selected enzyme wasNOVOZYM® 51081 from Novozymes. Enzyme was premixed with coagulant beforeapplying to pulp at designed addition levels. The microparticle used wasBUFLOC® 5461, Buckman Laboratories International, Inc., at a dosage of1.0 lb/ton (dry solids basis).

Testing Procedure:

An L₉(3⁴) Orthogonal Experimental Design was applied for thisexperimentation. This experimental design strategy is shown, forexample, in Hinkelmann, K., et al., (2008), Design and Analysis ofExperiments. I and II (Second ed.), Wiley, ISBN 978-0-470-38551-7, andGhosh, S., et al., (1996), Design and Analysis of Experiments. Handbookof Statistics, 13, North-Holland, ISBN 0-444-82061-2. Selected variablesand ranges are listed in Table 8. Experimental results and analysis forboth drainage and turbidity are summarized in Table 9-10.

A MüTek™ RDF tester was applied for all drainage tests to measuredrainage and turbidity. The testing furnish consistency was 1.0%. Thechemical addition program was to add coagulant first and follow withflocculant. To simulate white water circulation, the filtrate wascollected after testing and reused for next testing sample. The sampletemperature for testing was controlled as indicated.

TABLE 8 Variables and level Variables & Levels I II III Enzyme contentin 5 10 15 coagulant, wt % Contact time, min 0 20 40 Temperature, ° C.20 40 60 Coagulant type BUFLOC ® BUFLOC ® BUFLOC ® 5031 597 5551

TABLE 9 Experimental design and analysis for drainage Factor Enzymecontent Time Temp Drainage No. (wt %) (min) (° C.) Coagulant (g/50 sec)1 I I I I 296 2 I II II II 323 3 I III III III 387 4 II I II III 319 5II II III I 382 6 II III I II 299 7 III I III II 352 8 III II I III 3079 III III II I 357 K₁ 1006 967 902 1035 K₂ 1000 1012 999 974 K₃ 10161043 1121 1013 K₁ 335.3 322.3 300.7 345.0 K₂ 333.3 337.3 333.0 324.7 K₃338.7 347.7 373.7 337.7 R 5.3 25.3 73.0 20.3

Statistics analysis of the orthogonal experimental design was targetedto clarify the significance levels of the influence of all processfactors on drainage performance. The K_(i) was sum of drainage at level(i). The k_(i) value for each level of a parameter was the average offour values shown in Table 9, and the range value (R) for each factorwas the difference between the maximal and minimal value of the threelevels. Based on the results of range analysis, the importance of thecontributions of the studied factors to drainage is therefore ranked asfollows: Temperature>Time>Coagulant type>Enzyme dosage. The similaranalysis for turbidity is shown in Table 10. Time and Temperature showedsimilar impact on turbidity, which are the most significant factors forturbidity. Enzyme type and Dosage showed less important impact.

TABLE 10 Experimental design and analysis for turbidity Factor Enzymecontent Time Temp Turbidity No. (wt %) (min) (° C.) Coagulant (NTU) 1 II I I 483 2 I II II II 481 3 I III III III 466 4 II I II III 409 5 II IIIII I 524 6 II III I II 539 7 III I III II 436 8 III II I III 492 9 IIIIII II I 464 K₁ 1430 1328 1514 1471 K₂ 1472 1497 1354 1456 K₃ 1392 14691426 1367 k₁ 476.7 442.7 504.7 490.3 k₂ 490.7 499.0 451.3 485.3 k₃ 464.0489.7 475.3 455.7 R 26.7 56.3 53.3 34.7

With respect to effect on drainage, based on range analysis, thesignificance of all selected variables could be ranked in importance,from more important to less, as follows: a) temperature; b) contact timeand coagulant type; c) enzyme content level in coagulant. Within theexperimental range used, increasing enzyme content from 5% to 10% byweight, and to 15% by weight, combined into cationic coagulant did notshow significant effects on the drainage achieved at the lower enzymecontent, as shown in FIG. 12. Longer contact time normally improvesdrainage, as FIG. 13 shows. Temperature effects furnish drainage, asshown in FIG. 14. However, it should be noted that contribution oftemperature to drainage is not fully ascribed to activated enzyme, ashigher temperature is believed to have effect on fluidity of pulp andwater so to speed up drainage as shown in FIG. 16 in the case withoutenzyme added. Enzyme content in the combination of coagulant/enzyme isbased on total solids of coagulant and enzyme, which means that increasein enzyme content result in reduction in coagulant content. Since enzymeaddition in this experiment ranged from 5-15% on total solids in thecombination of coagulant/enzyme, coagulant percentage in the combinationranged from 95-85%. The result revealed that enzyme functioned toenhance drainage only when sufficient amount of coagulant could be used.At certain coagulant dosages, higher enzyme ratio in combination led toless amount of coagulant added in pulp furnish, and resulted in lowerdrainage. For the experiments shown in FIG. 16, some pulps were onlytested with one or the other indicated cationic coagulant (i.e., BUFLOC®5031 or BUFLOC® 5551), but not the enzyme, and other pulps were treatedwith a combined enzyme and a cationic coagulant (BUFLOC® 5031). Also,the selection of cationic coagulant for combination with the enzymedemonstrated some effect on the drainage results, as indicated in FIG.15. Among the tested coagulants, BUFLOC® 5031 showed the besteffectiveness with the enzyme on drainage, and effects on drainage seenwith pulps treated with BUFLOC® 5551 and BUFLOC® 597 also wereconsidered beneficial.

With respect to effects on turbidity, turbidity can be used forapproximation of retention performance. Results are summarized in Table10 and plotted in FIGS. 17-20. Both time and temperature showsignificant effect on turbidity, but quite different from the effect ondrainage. Extending time of enzyme in contact with cellulosic fibersincreases drainage but also increase turbidity, as FIG. 18 shows.Overall, higher temperature would reduce turbidity which implies theimprovement on retention, as shown in FIG. 19. Cationic coagulantselection also showed effects on turbidity results. Pulps treated withBUFLOC® 5551 exhibited the lowest turbidity when combined with enzyme,and effects on turbidity seen with pulps treated with BUFLOC® 5031 andBUFLOC® 597 also were considered beneficial. Enzyme content appears tobe a less significant factor as compared with others mentioned onturbidity, as FIG. 17 shows.

With respect to simulation of white water recirculation and impact onenzyme effect, a preliminary simulation of white water circulation wasrun to investigate the effect of enzyme in white water circulation. Theresults are shown as FIG. 21. An apparent increase in drainage wasobserved when run as a series of tests using circulated water. Theseresults indicate it is an efficient and feasible solution to extendcontact time of enzyme with fibers, which could overcome an obstacle ofenzyme application as a regular coagulant. Although not desiring to bebound to a particular theory, it is believed that the white waterrecirculation can allow added time for performance improvements to bemore fully obtained by the enzyme and cationic coagulant composition,and may show a benefit of adding the composition later in the process.

Applicants specifically incorporate the entire contents of all citedreferences in this disclosure. Further, when an amount, concentration,or other value or parameter is given as either a range, preferred range,or a list of upper preferable values and lower preferable values, thisis to be understood as specifically disclosing all ranges formed fromany pair of any upper range limit or preferred value and any lower rangelimit or preferred value, regardless of whether ranges are separatelydisclosed. Where a range of numerical values is recited herein, unlessotherwise stated, the range is intended to include the endpointsthereof, and all integers and fractions within the range. It is notintended that the scope of the invention be limited to the specificvalues recited when defining a range.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the embodiments of thepresent invention without departing from the spirit or scope of thepresent invention. Thus, it is intended that the present inventioncovers other modifications and variations of this invention providedthey come within the scope of the appended claims and their equivalents.

What is claimed is:
 1. A method of making paper or paperboardcomprising: a) applying a composition comprising enzyme and cationiccoagulant to a paper making pulp to form a treated pulp, wherein saidcomposition is added in a paper making process to the paper making pulpafter a white water silo and prior to at least one of a fan pump, ascreen, and a head box from which filtrate drained from pulp isrecirculated to said white water silo, wherein the composition comprisesfrom about 1% by weight to about 99% weight enzyme and from about 99% byweight to about 1% by weight cationic coagulant, on a dry solids weightbasis, and the composition is added to the pulp in an amount of from 0.5pound per ton to 10 pounds per ton based on the dried solids weight ofthe pulp; and b) forming the treated pulp into paper or paperboard,wherein pulp temperatures of the treated pulp during at leastsubstantially an entire time of contact of the composition with the pulpis maintained at from about 30° C. to about 60° C. and the time ofcontact is from about 1 minute to about 150 minutes.
 2. The method ofclaim 1, wherein the pulp is kept at a temperature or temperatures belowabout 40° C. prior to applying the composition to the pulp.
 3. Themethod of claim 1, wherein the enzyme is a cellulytic enzyme.
 4. Themethod of claim 1, wherein the enzyme is cellulase, hemicellulase,pectinase, β-glucanases, CMCase, amylase, glucosidase, galactosidase,lipase, protease, lacase, or any combinations thereof.
 5. The method ofclaim 1, wherein the enzyme is endoglucanase.
 6. The method of claim 1,wherein the cationic coagulant is a cationic organic polymer coagulant.7. The method of claim 1, wherein the cationic coagulant is a polyamine,polyacrylamide, polyamidoamine-glycol, polyvinylamine, polyethyleneimine, polydiallyldimethylammonium chloride, cationic starch, or anycombinations thereof.
 8. The method of claim 1, wherein the cationiccoagulant is a polyamine, polyamidoamine-glycol, polyvinylamine,polyethylene imine, or any combinations thereof.
 9. The method of claim1, wherein the cationic coagulant is an inorganic cationic coagulant.10. The method of claim 1, wherein the cationic coagulant ispolyaluminum chloride, aluminum sulfate, water-dispersible aluminamineral particles, aluminum sulfate, aluminum chloride, ferric chloride,ferric sulfate, polyaluminum sulfate, polyaluminum sulfate silicate,cationic alumina mineral particles, a cationic colloidal silica sol,aluminum chlorohydrate, or any combinations thereof.
 11. The method ofclaim 1, further comprising applying a flocculant to the pulp afterapplying the composition to the pulp and prior to paper forming.
 12. Themethod of claim 11, wherein the flocculant is added to the pulp in anamount of at least about 0.01 pound per ton based on the dried solidsweights of the pulp.
 13. The method of claim 1, wherein the drainage(g/50 sec) is at least about 5% greater than treatment of the pulpwithout the enzyme.
 14. The method of claim 1, wherein the turbidity(NTU) is at least about 5% less than treatment of the pulp without theenzyme.
 15. The method of claim 1, wherein said composition is added inthe paper making process to the paper making pulp after the white watersilo and prior to the fan pump.